Rugs and carpets are adaptable to being cleaned utilizing liquid detergent, foams, or dry powders. The dry powder cleaning method is preferred in many instances because there is no need to wait for the carpet to dry before traffic can be resumed and furniture moved back into place.
Cleaning carpets by the dry powder method is conventionally done in three steps. First, the dry powder is dispensed onto the carpet. Second, the powder is impinged into the nap of the carpet by a suitable brush means. Third, the residue is removed from the carpet. This final step of removing the residue can be accomplished by a vacuum cleaner. Although upright vacuum cleaners are generally used, any conventional vacuum cleaner such as a canister vacuum may also be used.
Conventionally, the first two of the three steps for cleaning carpets with a dry powder have been combined in a single apparatus, which dispenses the dry powder onto the carpet and impinges it into the nap of the carpet. U.S. Pat. No. 3,173,165 to Speigt discloses a liquid detergent applicator and a brush scrubbing means for impinging the detergent into the carpet. Speigt discloses the dispensing of a liquid detergent. Due to the differences in chemical adhesion between a liquid and powder, the teachings of Speigt are not adaptable to solving the problem of dispensing a dry powder.
U.S. Pat. No. 2,222,909 to LoCascio discloses an apparatus which is capable of dispensing dry powder onto a carpet and impinging the powder into the nap thereof. The apparatus disclosed therein utilizes a plurality of rotatable brushes mounted so as to contact the surface to be cleaned. One portion of the brush is exposed to a chamber in a hopper containing the dry powder. Powder is force fed to the brushes by a spring assisted piston which exerts a downward force on the powder within the chamber which is in communication with the brushes.
U.S. Pat. No. 3,289,240 to Vanderveer discloses a combination apparatus capable of dispensing dry powder and impinging it into the nap of a carpet. Vanderveer's apparatus comprises feed rollers in contact with both the floor surface and hopper. The hopper contains a plate of shorter length than the hopper which defines two apertures under which the rollers are mounted. The apertures are used as an orifice to determine the volume of dry powder deposited on the brushes thereunder.
U.S. Pat. No. 4,381,157 to Brown also discloses an apparatus capable of dispensing and impinging dry carpet powder. Brown's apparatus is similar to that of Vanderveer and LoCascio but utilizes a removable powder dispenser.
All of the aforementioned apparatus require the use of a conventional vacuum cleaner to remove the residue.
Speight, Locascio and Vanderveer all disclose an apparatus which dispenses and impinges the dry powder in one step. The drawback of combining the two steps, dispensing the powder and impinging it into the carpet, is the loss of effectiveness. The cleaning effectiveness is largely dependent on the degree of impingement of the powder into the nap of the carpet. In apparatus which combine the two steps the impingement is fixed and hence the cleanliness of the carpet cannot be improved substantially with additional impingement without depositing additional dry powder on the surface to be cleaned. This excessive use of dry powder can be very expensive.
The Brown apparatus teaches separating the dispensing and impingement into two separate steps. Impingment of the dry powder with the Brown apparatus is accomplished by lifting the machine from the floor and flipping it over such that the brush portion of the apparatus is in contact with the floor. The brush is then guided manually back and forth over the surface by the operator. The cleanliness of the carpet will be dependent largely on the degree to which the dry powder is worked into the nap of the carpet. Utilizing the Brown apparatus, the operator will have to repeatedly go over the same path.
Conventional apparatus also require that the operator lift the apparatus from the floor so as to carry it to a desired location. With a hopper full or partially full of dry powder, the apparatus can be quite heavy. A more desirable apparatus would be one in which the apparatus would not have to be lifted from the floor and carried. Preferably it could be pushed across the floor. However, if the roller is not covered, some additional dry powder will be deposited on the floor surface while the apparatus is being transported. This makes it necessary for the operator to revacuum some portions of the carpet.
To be effective the powder used as a cleaning agent must be kept fresh--maintained at a certain moisture content. Once the powder drys out it is ineffective as a cleaning agent. The shelf life is a non-sealed container is relatively short--8 hours or less. The hoppers in conventional apparatus are not sealed. Hence, the powder must be removed from the apparatus after each use and stored in sealed container.